Tractor trailer combinations generally require a braking system on the trailer that is engaged when a braking system of the tractor is selectively engaged. Often the braking system of the trailer is coupled to the braking system of the tractor to allow the tractor to simultaneously apply the braking system of the tractor and the trailer. Current trailer brake control circuits typically utilize a single trailer brake valve with a fixed hydraulic gain. When the brakes of the tractor are applied, a pilot pressure controls the single trailer brake valve. The single trailer brake valve provides hydraulic fluid and pressure to the braking system of the trailer under fixed gain conditions.